You will be plugging the Arduino into the computer for serial communication with the computer (and Max). Most Arduino boards have a USB port that provides power to the device. We tap into that power for the simple circuit we've created.

We use digital pins 2 - 5 for our LED display. You generally don't want to use pins 0 and 1, since they are used for serial communication.

In order to prevent overtaxing the power supply of the Arduino, use use the 1K resistors as "current limiting resistors" - they reduce the amount of current drawn from the Arduino board, and prevent the LEDs from burning out.

Now that we have our circuit ready, let's create an Arduino sketch that tests our board, and prepares it for communication with Max.